1. Field of the Invention
The present invention relates generally to cosmetic compositions and their use in reducing wrinkles and spots of hyperpigmentation of the skin. More particularly, the compositions comprise an amino acid derivative, 3-phenylacetylamino-2,6-piperidinedione, in a cosmetically acceptable vehicle.
2. Related Art
Wrinkles are usually a natural consequence of aging. By age twenty-five, a person usually observes some facial wrinkles which accompany cutaneous age-related changes. These changes include loss of subdermal fat, a diminution of muscle tone, and a loss of elasticity. These changes parallel a decrease in collagen and elastin fiber content. Hormonal changes also occur and are linked to a decrease in the water-binding capacity of the skin tissue. In addition to aging, wind, sunlight and disease are among other contributing causes of skin wrinkles. Either singly, on in combination, these forces promote inelasticity and drying of skin tissues.
Hyperpigmentation is generally related to dense melanin concentrations in skin tissues. The color of skin is determined by the amount and size of melanin accumulation. Hyperpigmentation of the skin occurs when there is an increased production of melanin. Spots of hyperpigmentation may result from natural phenomena or they may be caused by external stress, drugs, or other dysfunctions. Most common types of localized hyperpigmentation includes: lentigo, ephelis (freckles), nevus and melasma. The last type corresponds to hyperpigmentation in pregnant women or women taking oral contraceptives and is due to increased level of melanocyte-stimulating hormone and adrenocorticotrophic hormone produced by the pituitary gland.
Historically, the use of cosmetic preparations dates from the teachings of the Egyptian scribes. Herbs and other plant extracts served as the basis of such preparations. In the early 1900's physicians introduced phenol for the treatment of acne. Chemosurgery, or cutaneous peeling, following phenol application became quite popular for the removal of facial wrinkles as well. Techniques of "subdermal filling" also gained acceptance. Paraffin and, later, organosilicone polymers were injected into the skin tissues to "fill out" wrinkles.
Presently, anti-wrinkle preparations are found in a variety of forms including aerosols, foams, lotions, ointments, creams or gels. Lanolins, phospholipids, sterols and fatty acids are common vehicles. An emulsifier is usually included in such preparations to obtain the desired viscosity and stability. Preservatives, such as paraaminobenzoic acid, are also included to prevent contamination.
A variety of cosmetic preparations are currently used. For instance, emollients are generally used to promote skin smoothness. Their topical effect has been attributed to either the prevention of further water loss from the skin or the attraction of water to skin tissues. Hormonal compositions are similarly used to smooth wrinkles. The topical application of certain hormones has been related to the hydration of epidermal cells. Collagen extracts are also currently used to enhance the skin's smoothness. Injected into the dermis, these preparations become vascularized and incorporated into the established collagen network, subsequently replacing the lost fiber.
To enhance even color tone of the skin, cosmetologists have used hydroquinone. Hydroquinone lightens areas of hyperpigmentation.
While topically applied preparations exert short term effects, they generally fail to produce any lasting benefit. Consumers spend millions of dollars for such "anti-wrinkle" preparations annually. The compositions which are injected intradermally do perhaps exert a longer lasting effect, but are expensive and require a physician's skill. It is, therefore, apparent that a cosmetic which is topically applied and long lasting in effect would be most desirable. The present cosmetic compositions provide these features. They are easily applied and have a prolonged effect in reducing wrinkles and spots of hyperpigmentation.